Selective fat removal using photothermal heating

Abstract

A system and method are provided for minimally-invasive selective fat removal from a target area by injecting the area with a solution of photo-absorbing nanoparticles and irradiating the injected area with a beam of near infrared (NIR) light. The NIR emission wavelength excites the nanoparticles to melt fat within the target area so that the liquefied fat can be aspirated from the target area. The nanoparticles may be gold nanorods having aspect ratios selected to produce surface plasmon resonance when irradiated with NIR light around 800 nm.

The invention claimed is: 
     
       1. A system for selective removal of fat in a subject in need thereof, comprising: a solution comprising gold nanorods suspended in a biocompatible liquid at a concentration range of 10 11  to 10 13  GNR/mL; an injector configured for distributingthe solution within a target area comprising adipose tissue located beneath a skin surface; a light source configured for delivering a series of pulses of near infrared light across the skin surface and into the target area for an exposure duration to induce surface plasmon resonance in the nanorods, wherein the light source comprises a system controller for generating control signals for controlling a combination of optical parameters selected from the group consisting of beam energy, pulse duration, emission wavelength within a range of 700 to 900 nm, emission intensity, beam focus and beam area, wherein the system controller is configured to select the optical parameters and the exposure duration to excite the nanorods to liquefyfat within the target area and to modulate heating of tissue adjacent the fat. 
     
     
       2. The system of  claim 1 , wherein the light source is further configured for scanning across the target area in a plurality of passes. 
     
     
       3. The system of  claim 1 , further comprising a cooling material configured for application to an area of skin overlying the target area. 
     
     
       4. The system of  claim 1 , wherein the emission wavelength is 800 nm+10 nm. 
     
     
       5. The system of  claim 1 , wherein the gold nanorods have an aspect ratio in the range of 1:3-1:5. 
     
     
       6. The system of  claim 1 , wherein the gold nanorods having an axial diameter of approximately 10 nm and a longitudinal diameter in the range of 9 to 50 nm. 
     
     
       7. The system of  claim 1 , wherein the solution further comprises an anesthetic tumescent solution. 
     
     
       8. The system of  claim 1 , wherein the gold nanorods are functionalized with poly(ethylene-glycol). 
     
     
       9. The system of  claim 1 , wherein the beam area is within a range of 9 mm×9 mm to 35 mm×35 mm. 
     
     
       10. The system of  claim 9 , wherein the beam area is 2.3 cm×3.5 cm. 
     
     
       11. The system of  claim 1 , wherein the beam energy is in a range of 1000 to 2000 J. 
     
     
       12. The system of  claim 1 , wherein the pulse duration is within a range of 30 ms to 60 ms. 
     
     
       13. A system for selective fat removal in a subject in need thereof, comprising:
 a suspension of photo-absorbing gold nanoparticles having an aspect ratio in a range of 1:3 to 1:5 in a biocompatible solution; 
 an injector configured for subcutaneously injecting the suspension into a target area of adipose tissue of the subject; and 
 a near infrared light source configured for delivering a series of light pulses to the target area, the near infrared light source comprising a system controller for generating control signals controlling delivery parameters of a light beam, wherein the control signals comprise selection of an emission wavelength within an emission wavelength range of 700 to 900 nm, an emission intensity and an exposure duration, and wherein the system controller is configured to select the emission wavelength to excite the nanoparticles to generate heat to melt and liquefy fat within the target area and the emission intensity and exposure duration to modulate heating of tissue adjacent the fat. 
 
     
     
       14. The system of  claim 13 , wherein the near infrared light source is further configured for scanning across the target area in a plurality of passes. 
     
     
       15. The system of  claim 13 , further comprising a cooling material configured for application to an area of skin overlying the target area. 
     
     
       16. The system of  claim 13 , wherein the emission wavelength is 800 nm+10 nm. 
     
     
       17. The system of  claim 13 , wherein the gold nanoparticles are gold nanorods having an axial diameter of approximately 10 nm and a longitudinal diameter in the range of 9 to 50 nm. 
     
     
       18. The system of  claim 13 , wherein the biocompatible solution further comprises an anesthetic tumescent solution. 
     
     
       19. The system of  claim 13 , wherein a beam area of the light beam is within a range of 9 mm×9 mm to 35 mm×35 mm. 
     
     
       20. The system of  claim 13 , wherein a beam energy of the light beam is in a range of 1000 to 2000 J. 
     
     
       21. The system of  claim 13 , wherein a pulse duration within the series of light pulses is within a range of 30 ms to 60 ms.